Total Body Potassium Research Articles

Whole body counter calibration using Monte Carlo modeling with an array of phantom sizes based on national anthropometric reference data

During construction of the whole body counter (WBC) at the Children's Nutrition Research Center (CNRC), efficiency calibration was needed to translate acquired counts of 40K to actual grams of potassium for measurement of total body potassium (TBK) in a diverse subject population. The MCNP Monte Carlo n-particle simulation program was used to describe the WBC (54 detectors plus shielding), test individual detector counting response, and create a series of virtual anthropomorphic phantoms based on national reference anthropometric data. Each phantom included an outer layer of adipose tissue and an inner core of lean tissue. Phantoms were designed for both genders representing ages 3.5 to 18.5 years with body sizes from the 5th to the 95th percentile based on body weight. In addition, a spherical surface source surrounding the WBC was modeled in order to measure the effects of subject mass on room background interference. Individual detector measurements showed good agreement with the MCNP model. The background source model came close to agreement with empirical measurements, but showed a trend deviating from unity with increasing subject size. Results from the MCNP simulation of the CNRC WBC agreed well with empirical measurements using BOMAB phantoms. Individual detector efficiency corrections were used to improve the accuracy of the model. Nonlinear multiple regression efficiency calibration equations were derived for each gender. Room background correction is critical in improving the accuracy of the WBC calibration.

Body composition changes over 9 years in healthy elderly subjects and impact of physical activity

Age-related changes of body composition affect health status. This study aims at clarifying body composition changes in healthy elderly subjects, and evaluating the impact of physical activity on these changes. In 1999, 213 subjects≥65 years recruited through advertisements underwent assessment of health state, energy expenditure by physical activity, body composition by bioimpedance analysis and body cell mass by total body potassium. In 2008, 112 of them repeated these assessments with additional determination of Barthel index, Mini Mental State Examination and Geriatric Depression Score. Lean tissues decreased in both genders (p<0.05). Compared to subjects aged 65-74 years at baseline, those aged ≥75 years lost more body weight (men: -3.7±5.4 vs. 0.4±5.4kg, women: -3.6±5.5 vs. 0.3±5.2kg, both p<0.05), and fat-free mass (men: -3.6±3.3 vs. -0.4±2.7kg, women: -1.8±2.3 vs. -0.1±2.5kg, both p<0.05). Plotting of fat-free mass evolution against age at baseline showed an exponential loss of fat-free mass. Increased physical activity limited lean tissue loss in men but not in women. Loss of lean tissues occurs exponentially with aging. Further research should confirm these changes in subjects over 80 years. Increasing physical activity limits fat-free mass loss in men but not women.

Prevalence of hypokalemia in ED patients with diabetic ketoacidosis

ObjectiveAlthough patients with diabetic ketoacidosis (DKA) are expected to have total body potassium depletion, measured levels may be normal or elevated due to extracellular shifts of potassium secondary to acidosis. Because insulin therapy decreases serum potassium levels, which creates potential to precipitate a fatal cardiac arrhythmia in a patient with hypokalemia, the American Diabetes Association (ADA) recommends obtaining a serum potassium level before giving insulin. Although the ADA guidelines are clear, the evidence on which they are based is largely anecdotal. The purpose of this study was to estimate the prevalence of hypokalemia in patients with DKA before initiation of fluid resuscitation and insulin therapy. MethodsThis is a prospective cross-sectional descriptive study of patients with a capillary blood glucose level of 250 mg/dL or higher (at risk for DKA) seen in an urban county emergency department over a 1-year period. Those who consented provided basic demographic information and had a venous blood gas and chemistry panel drawn. Diabetic ketoacidosis and hypokalemia were defined using ADA recommendations. ResultsThe mean age in our sample was 40.2 years, and 81% of patients were Hispanic. Of 503 analyzable patients with hyperglycemia, 54 (10.7%) met all criteria for DKA. Of patients with DKA, 3 (5.6%) of 54 (95% confidence interval, 1.2%-15.4%) had hypokalemia. Two of these patients had values of 3.0 mmol/L, and 1 had a value of 2.8 mmol/L. ConclusionHypokalemia was observed in 5.6% of patients with DKA. These findings support the ADA recommendation to obtain a serum potassium before initiating intravenous insulin therapy in a patient with DKA.

A high-sensitivity multidetector whole-body counter

A prototype multidetector shadow-shield whole-body counter is presented to be used as a monitor of internal contamination and as a tool in clinical research. The counter is equipped with 16 NaI(Tl) detectors located in the central region of a shielded tunnel surrounding the subject to be measured. The accuracy of the counting efficacy predictions was tested in a group of adults with various body shapes and sizes using X-ray absorptiometry. The precision of the total body potassium measurements allows the use of the counter in clinical follow-up studies.

Hyponatremia and Hypokalemia in Patients on Peritoneal Dialysis

Hypokalemia occurs in up to 60% of patients on peritoneal dialysis (PD) for end-stage renal disease. It can be associated with poor clinical outcomes, including malnutrition and death. New evidence points to a link between hypokalemia and the risk of peritonitis. The serum Na(+) concentration is determined by the ratio of exchangeable Na(+) and K(+) to total body water. Hyponatremia may be caused by excessive thirst, a particular problem in patients on PD. Consistent with the relationship among the serum sodium concentration, total body cation content, and total body water, hyponatremia may also be caused by total body potassium depletion. Ultra-low sodium dialysis fluid may prove to have an important role in management of fluid overload and hypertension in patients on PD. Surprisingly, it is not associated with significant hyponatremia, for reasons that remain to be elucidated.

Longitudinal Study of Total Body Potassium in Healthy Men

Objectives: Total body potassium (TBK) is an index of fat-free mass and an accurate measure of body cell mass (BCM). To date, however, no longitudinal studies have evaluated body composition using TBK in aging healthy adults. The purpose of this study was to assess TBK and BCM in healthy men over a 21-year period, and to evaluate changes with age.Design: A 21-year longitudinal, prospective, observational study evaluating TBK and BCM and their relationship to changes with aging and body mass index (BMI).Subjects: Body composition of 133 healthy Italian men, 20 to 66 years of age, was measured by whole-body counting of 40K. TBK was calculated by using this formula: 40K × 8.474. BCM was calculated from TBK by using this formula: BCM (kg) = 0.00833 × TBK (mmol).Results: The prevalence of overweight and obesity increased significantly from baseline to end of study (p < 0.01), with no change in TBK observed over the 21-year period. BCM summaries were tested to determine if any was a good predictor of BMI after age 30. Participants with a low maximum BCM (<27 kg) at an early age tended to exhibit decreased BMI as they aged, whereas those with a high maximum BCM (>27 kg) at an early age tended to show increased BMI as they aged.Conclusion: Despite an overall increase in the incidence of overweight and obesity over the 21-year period, a high maximum BCM at an early age was a predictor of an increase in BMI as men got older.

Preoperative body composition is influenced by the stage of operable pancreatic adenocarcinoma but does not predict survival after Whipple's procedure

ObjectivesCachexia is common in pancreatic cancer and may have an influence on longterm survival but few studies have investigated this in patients with operable tumours. Therefore, this study was carried out to document body composition status in patients with pancreatic adenocarcinoma (PCa) presenting for a Whipple's procedure (WP) and to relate the findings to histopathology and longterm survival. MethodsBody composition was measured 1 day before a WP for ductal PCa in 36 patients (15 men, 21 women) aged 41–81 years. Results for total body nitrogen (TBN), nitrogen index (NI), total body water (TBW), fat mass (FM) and total body potassium (TBK) were compared with results in 73 age- and sex-matched controls. Patients' survival and details from histopathology synoptic reports were documented. ResultsPatients undergoing WPs had low TBK values (P < 0.001) and females had lower body fat (P= 0.007) compared with controls. Five of 36 presented with significant protein deficiency, but this was not associated with a prolonged length of stay or reduced survival. The 12 patients who had involved surgical margins had larger tumours and reduced weight (P= 0.015), FM (P= 0.001), TBN (P= 0.045), TBK (P= 0.014) and survival (P= 0.036). However, multivariate Cox's regression analysis only included FM along with vascular invasion and margin status as independent predictors of survival. ConclusionsPCa patients undergoing a WP have reduced body fat and TBK compared with community controls while those with stage III tumours had greater deficits of fat, TBK and protein stores. However, preoperative body composition was a poor predictor of postoperative survival after pathological data were considered.

Cortisol Regulation in the Metabolic Syndrome. A Novel Therapeutic Approach

The metabolic syndrome is characterized by visceral obesity, insulin resistance, Type 2 diabetes, dyslipidemia and hypertension. All these disturbances are also typically associated with cortisol hyperactivity, such as Cushing s syndrome. Therefore, it seems worthwhile to consider increased cortisol activity in the metabolic syndrome, despite normal circulating levels, to be an important pathogenetic mechanism. Thirty women, 49-65 yr old, with visceral obesity, insulin resistance and Type 2 diabetes were treated with ketoconazole 400 mg daily, in order to down-regulate cortisol activity, in a 3-month randomized, double-blind, placebo-controlled trial. The insulin resistance was evaluated with an euglycemic, hyperinsulinemic glucose clamp. Body fat was assessed from total body potassium. During the study, insulin resistance improved in the ketoconazole-treated group as compared to the placebo-treated one (p < 0.05). Total cholesterol (p < 0.05), fasting glucose (p < 0.05) and HbA1c (p < 0.05) levels decreased, whereas serum triglyceride levels and insulin concentrations were unaffected by the ketoconazole treatment. Systolic (p < 0.05) and diastolic (p < 0.05) blood pressure decreased in the ketoconazole treated group. Body fat was unchanged in both groups. Furthermore, liver AST (p < 0.05), ALT (p < 0.05) and ALP (p < 0.05) decreased in response to ketoconazole treatment. This study has demonstrated that a down-regulation of cortisol secretion can favorably affect most of the multiple risk factors associated with the metabolic syndrome. This includes improvement in insulin resistance, glucose homeostasis, total cholesterol, blood pressure and hepatic steatosis. Keywords: Metabolic syndrome, type 2 diabetes, insulin resistance, cortisol, blood lipids, hypertension, hepatic steatosis, visceral obesity, dyslipidemia, ketoconazole, euglycemic, hyperinsulinemic glucose clamp, glucose homeostasis, microalbuminuria, hyper-secretion, transgenic mouse model, dexametasone tests, HDL-cholesterol, Liver tests, aspartate amino-transferase, alanine amino-transferase, anticubital vein, isotonic saline, catheter, Glucose infusion rate, Anthropometry, sulfonylurea, metformin, Serum Bilirubin, Estradiol, dyspepsia, hypothalamic-pituitary-adrenal, cortisol hyperactivity, lipoprotein lipase, glucocorticoid receptors, gluconeogenesis, intrinsic mineralocorticoid, non-alcoholic steatohepatitis, free fatty acid, etiological factors

A tale from the Crypt: splice variants of BK channels in colonic potassium secretion

A tale from the Crypt: splice variants of BK channels in colonic potassium secretion

Bioelectrical impedance spectroscopy in growth hormone-deficient adults

This study evaluated water compartment assessment by bioelectrical impedance spectroscopy (BIS) by Xitron 4000B in 164 growth hormone-deficient adults on growth hormone replacement therapy, examined the assumed constant body density and gender-specific resistivities in BIS methodology and evaluated a published BMI-adjusted BIS equation. Body composition was measured by BIS, total body potassium (TBK), tritium dilution and dual-energy x-ray absorptiometry (DXA). Tritium dilution and TBK were combined to a reference method for water compartments. Average difference for total body water (TBW) by tritium dilution and by BIS was 0.6 l in women (p > 0.05) and −0.2 l in men (p > 0.05). Average extracellular water (ECW) by the reference method and by BIS differed 1.5 l in women (p < 0.05) and 1.2 l in men (p < 0.05). Average intracellular water (ICW) by the reference method and by BIS differed −0.9 l in women (p < 0.05) and −1.3 l in men (p < 0.05). However, average ECW and ICW could be successfully estimated by BIS with use of unisex resistivity constants that were derived from this population, although with large individual variation. Average individual body density was lower than assumed. Application of individual body density did not improve agreement between methods. BMI-adjusted equations were not fully accurate in this population.

Adipocyte size predicts incidence of type 2 diabetes in women

Enlarged subcutaneous abdominal adipocytes have been shown to predict incidence of type 2 diabetes (T2D) in the Pima population of Arizona (USA). We investigated the role of subcutaneous abdominal adipocyte size (AAS), as well as femoral adipocyte size (FAS), as predictors of T2D in a population-based Swedish cohort. In 1974-1975, a sample of 1302 middle-aged women underwent a health examination, including anthropometry and evaluation of parental medical history. In addition, body composition (total body potassium and total body water), AAS and FAS (adipose tissue needle biopsy) were assessed in a subsample of 245 women. Incidence of T2D was followed until 2001, with 36 cases eligible for inclusion in this analysis. Women developing T2D had larger AAS at baseline vs. women remaining healthy (age/heredity-adjusted hazard ratio for increase of AAS by 1 sd [AAS-HR] 1.91; P<0.001). Further adjustment for both body fat percentage and waist-to-height ratio (WHtR) indicated a robust association. For FAS, the corresponding associations were consistently weaker. WHtR retained a strong predictive association independent of AAS and FAS (WHtR-HR 2.6 and 2.7, respectively; P<0.001). To conclude, in addition to the amount and distribution of body fat in women, subcutaneous adipocyte size, particularly in the abdominal region, predicts incidence of T2D in later life.

Dual‐energy X‐ray absorptiometry is the method of choice to assess body composition in COPD

Mortality and morbidity in COPD have been related to reduced FEV1 as well as indices of body composition. Different techniques used to evaluate body composition may vary in accuracy, particularly in conditions with altered fluid balance such as COPD. We hypothesized that direct measurement of fat-free mass index (FFMI) by dual-energy X-ray absorptiometry (DEXA) would provide superior assessment of body composition in COPD. We measured body composition in 31 patients with COPD randomly selected from a teaching hospital clinic. To estimate total body water (TBW) and FFMI, skin-fold anthropometry, bioelectrical impedance analysis (BIA) with Schols and Lukaski equations as well as DEXA, total body potassium by whole-body gamma-counting (TBK) and in vivo neutron activation analysis were used. Combined body composition methods providing precise estimations of TBW were used for comparisons. Bland-Altman analyses, ANOVA and chi2-testing were used to examine data. Mean BMI was 27.6 +/- 5.34 kg/m2 (mean +/- SD). Estimations of TBW were similar using Schols BIA or by using combined body composition methods. FFMI did not vary significantly between grades of COPD severity but was significantly different when assessed using DEXA and other methods. Calculated FFM hydration was significantly different from the fixed hydration factor used to calculate FFMI from BIA TBW (P < 0.05). The Schols BIA method incorporates a fixed hydration factor that may lead to an erroneous estimation of FFMI with ensuing clinical implications. DEXA can be used to obtain accurate and comprehensive assessments of body composition and should be the preferred investigation in COPD.

Loop Diuretics Can Cause Clinical Natriuretic Failure: A Prescription for Volume Expansion

Ultrafiltration enhances volume removal and weight reduction vs diuretics. However, their differential impact on total body sodium, potassium, and magnesium has not been described. Fifteen patients with congestion despite diuretic therapy had urine electrolytes measured after a diuretic dose. Ultrafiltration was initiated and ultrafiltrate electrolytes were measured. The urine sodium after diuretics (60+/-47 mmol/L) was less than in the ultrafiltrate (134+/-8.0 mmol/L) (P=.000025). The urine potassium level after diuretics (41+/-23 mmol/L) was greater than in the ultrafiltrate (3.7+/-0.6 mmol/L) (P=.000017). The urine magnesium level after diuretics (5.2+/-3.1 mg/dL) was greater than in the ultrafiltrate (2.9+/-0.7 mg/dL) (P=.017). In acute decompensated heart failure patients with congestion despite diuretic therapy, diuretics are poor natriuretics and cause significant potassium and magnesium loss. Ultrafiltration extracts more sodium while sparing potassium and magnesium. The sustained clinical benefits of ultrafiltration compared with diuretics may be partly related to their disparate effects on total body sodium, potassium, and magnesium, in addition to their differential efficacy of volume removal.

Severe Hypokalemia, Paralysis, and AIDS-Associated Isospora Belli Diarrhea

Background: Hypokalemia of clinical significance, severe enough to cause paralysis and cardiac dysrhythmias, is an uncommon life-threatening medical disorder. Hypokalemic periodic paralysis (HPP), where an abrupt intracellular shift of potassium has occurred, must be distinguished from hypokalemic non-periodic paralysis (non-HPP), where a total body potassium deficit exists. The challenge for emergency physicians is to swiftly and accurately differentiate disease etiology and institute prompt treatment. Aggressive potassium repletion, required in non-HPP etiologies, may predispose HPP patients to dangerous and potentially fatal rebound hyperkalemia as the intracellular potassium shift resolves. Objectives: Describe the process by which HPP and non-HPP can be differentiated on clinical and laboratory grounds leading to appropriate resuscitation from severe and clinically relevant hypokalemia. Chronic diarrhea syndromes and possibly normal alkaline phosphatase levels alert the clinician to the potential for non-HPP. Case Report: A case of HIV/AIDS-associated isospora belli diarrheal illness with severe hypokalemia of the non-HPP type is presented. Historical, laboratory, and clinical findings, which assisted in the differentiation from HPP, are emphasized. Clinical progression and treatment strategies, as well as electrocardiogram findings with T-U-P fusion waves, are described in detail. Conclusion: The history, especially the time course of disease, is essential in differentiating HPP and non-HPP, allowing treatment to proceed without overcorrection and rebound hyperkalemia. Although other infectious diseases have been linked to non-HPP, to our knowledge this is the first report linking non-HPP to isospora belli diarrheal illness.

CHANGES IN BODY COMPOSITION: MUSCLE FUNCTION AND ENERGY EXPENDITURE AFTER RADICAL CYSTECTOMY

BJU InternationalVolume 102, Issue 10 p. 1478-1479 CHANGES IN BODY COMPOSITION: MUSCLE FUNCTION AND ENERGY EXPENDITURE AFTER RADICAL CYSTECTOMY Anthony J. Koupparis, Anthony J. Koupparis Urology, Cheltenham General Hospital, Cheltenham, UKSearch for more papers by this authorHabiba Nabti, Habiba Nabti Urology, Cheltenham General Hospital, Cheltenham, UKSearch for more papers by this author Anthony J. Koupparis, Anthony J. Koupparis Urology, Cheltenham General Hospital, Cheltenham, UKSearch for more papers by this authorHabiba Nabti, Habiba Nabti Urology, Cheltenham General Hospital, Cheltenham, UKSearch for more papers by this author First published: 23 October 2008 https://doi.org/10.1111/j.1464-410X.2008.08188_3.xRead the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Volume102, Issue10November 2008Pages 1478-1479 RelatedInformation

The reduction in visceral fat mass in response to growth hormone is more marked in men than in oestrogen-deficient women

Context Women with severe growth hormone (GH) deficiency have a less marked response to GH replacement than men. This has mostly been attributed to the attenuating effects of oestrogen replacement therapy. Objective To study gender related differences in the response to GH treatment in men and postmenopausal women. Methods Fifteen men and 15 age- and BMI-matched women with abdominal obesity (mean age: 58; range 51–64 years) were treated for one year with similar doses (0.47 vs. 0.51 mg/day) of GH. All women were postmenopausal not receiving oestrogen treatment. Insulin sensitivity was assessed using a hyperinsulinemic euglycemic clamp and body composition by computed tomography (CT) scans and from total body potassium, K 40. Results Men and women were comparable at baseline in terms of waist circumference, IGF-1 and lipid levels. After one year of GH treatment, there was a 18% reduction in visceral adipose tissue (VAT) in men and a 5% reduction in women ( P = 0.0001 men vs. women). Although the magnitude of the difference was small, men increased more in thigh muscle mass ( P < 0.0001 vs. women). A reduction in thigh intermuscular adipose tissue (IMAT) and diastolic blood pressure was seen only in men (both p < 0.05 vs. baseline). A decrease in LDL cholesterol, and an increase in serum insulin, was observed only in women (both p < 0.05 vs. baseline). Conclusion Low dose GH treatment reduced VAT more markedly in men as compared with women. As all women were postmenopausal and oestrogen-deficient, this gender difference in responsiveness was not due to an antagonistic effect of oestrogen on peripheral GH action.

Evaluation of between-methods agreement of extracellular water measurements in adults and children

BackgroundExtracellular water (ECW), a relevant molecular level component for clinical assessment, is commonly obtained by 2 methods that rely on assumptions that may not be possible to test at the time the measurements are made. ObjectiveThe aim of the current study was to evaluate the degree of agreement between ECW assessment by the sodium bromide dilution (ECWNaBr) and total body potassium (TBK; whole-body 40K counting) to total body water (TBW; isotope dilution) methods (ECWTBK-TBW) in an ethnically mixed group of children and adults. DesignECW was measured with the ECWNaBr and ECWTBK-TBW methods in 526 white and African American males and females (86 nonobese children, 193 nonobese adults, and 247 obese adults). Fat mass was assessed with dual-energy X-ray absorptiometry. Multiple regression analysis was used to examine the variables related to between-ECW method differences. ResultsSignificant but generally small group mean (±SD) differences in ECW were found in the obese adults (1.28 ± 2.54 kg) and children (−0.71 ± 1.78 kg). The magnitude of the differences was related to mean ECW in obese adults, children, and nonobese adults, and the relations between these variables were modified by sex for nonobese adults. ECW differences were also dependent on age, weight, sex, and race or on interactions between these variables. ConclusionsOverall, although good between-method agreement was found across the 3 groups, the degree of agreement varied according to subject characteristics, particularly at the extremes of ECW and body weight. We advance a possible mechanism that may link subject characteristics with the degree of agreement between ECW measurement methods and their underlying assumptions.

Comparison of different nutritional assessments and body-composition measurements in detecting malnutrition among gynecologic cancer patients

BackgroundFew studies have assessed global nutritional assessment tools and body-composition measurements in gynecologic cancer patients. ObjectiveWe aimed to assess the convergent validity of different nutritional tools such as the scored Patient-Generated Subjective Global Assessment (PG-SGA), serum albumin, skinfold-thickness measurements, and total-body potassium (TBK) and body density measurements to identify gynecologic cancer patients at risk of malnutrition. DesignWe assessed the nutritional status of 194 patients with suspected or proven gynecologic cancer according to the SGA and the scored PG-SGA, and skinfold-thickness (n = 145), TBK (n = 51), and body density measurements (n = 42) before primary treatment. ResultsAccording to the SGA and the scored PG-SGA global rating, 24% of gynecologic cancer patients were classified as malnourished. The prevalence of malnutrition was highest in ovarian (67%) and lowest in endometrial (6%) cancer patients. The ability of the PG-SGA score (P < 0.001) and albumin (P < 0.001), triceps skinfold-thickness (P = 0.041), and TBK (P = 0.005) measurements to predict the SGA was significantly better than chance. TBK significantly correlated with measurements associated with protein depletion, including age (P < 0.001), arm muscle area (P < 0.001), fat-free mass (P < 0.001), and the PG-SGA score (P = 0.009). Multiple regression analysis showed that, together, the PG-SGA score and arm muscle area adjusted for age accounted for 66% of total TBK variance. ConclusionsThe PG-SGA is significantly associated with subjective and objective parameters and is a widely recognized, clinically relevant method of evaluating nutritional status. It therefore seems most appropriate for identifying malnourishment in gynecologic cancer patients.

Nutritional status of patients undergoing pelvic exenteration for primary or recurrent rectal cancer

Methods: 24 participants with Childs Pugh class B cirrhosis [17males:7females, mean age (range) 52.5(38-64)years] completed 2 months of study protocol. 12 participants were randomised into BCAA group, took 3 sachets (4g BCAA/ sachet) of BCAA supplement daily between meals and attended monthly clinic visits. 12 participants were randomised into Placebo group, took 3 sachets of a isonitrogenous supplement daily between meals and attended monthly clinic visits. At each clinic visit clinical assessments were made, serum samples were collected, then total body nitrogen (TBN) and total body potassium (TBK) were measured. The results of baseline and monthly measurements were compared using independent samples t-tests. Results: The Placebo group showed a greater increase (p 0.05) in TBN at month 2, TBK at months 2 and 3 than the BCAA group. The BCAA group showed a significant decrease (p 0.05) in serum GGT and ALP at month 3 compared to the baseline and the Placebo group. IGF-1 levels showed no significant change. Conclusion:

Changes in body composition, muscle function and energy expenditure after radical cystectomy

To determine the changes in body composition, muscle function and energy expenditure after radical cystectomy (RC). Eleven consecutive men (median age 66 years, range 44-79) who had a RC over a 1-year period had measurements made of their total body protein, by neutron-activation analysis, total body water by tritium dilution, total body potassium by whole-body counting, resting energy expenditure by indirect calorimetry, and grip strength and respiratory muscle strength. These variables were measured on the day before surgery and at 2 weeks and 6 months after RC. Total body fat was derived using a multicompartment model. Artificial nutritional support was not provided after RC and no oral caloric intake was provided until bowel function returned. Five patients were malnourished before RC and four had significant complications afterward. Over the first 2 weeks there were significant losses in mean (sem) protein levels, at 0.68 (0.17) kg (P < 0.001) and water, at 3.00 (0.73) L (P < 0.001), while body fat was unchanged. Resting energy expenditure was 11% higher than predicted at 14 days after RC (P < 0.001). Body potassium changes mirrored the protein changes but were not statistically significant. Over the subsequent 6 months, 63%, i.e. 0.43 (0.24) kg, of the body protein lost after surgery was regained. Muscle function had returned to baseline levels at 6 months. This study shows that the catabolic loss of body protein after RC is not regained by 6 months. Regimens directed at early nutritional support after RC for these patients might improve the recovery of body composition, with consequent clinical benefits.